Updated to add test as suggested in PR

Author: rainkwan

internal/fwserver/server_listresource.go

@@ -87,11 +87,16 @@ var NoListResults = func(func(ListResult) bool) {}
 func (s *Server) ListResource(ctx context.Context, fwReq *ListRequest, fwStream *ListResultsStream) {
 	listResource := fwReq.ListResource
 
-	if fwReq.Config == nil {
+	if fwReq.Config == nil && fwReq.ResourceSchema != nil {
 		fwReq.Config = &tfsdk.Config{
 			Raw:    tftypes.NewValue(fwReq.ResourceSchema.Type().TerraformType(ctx), nil),
 			Schema: fwReq.ResourceSchema,
 		}
+	} else if fwReq.Config == nil && fwReq.ResourceIdentitySchema == nil {
+		fwReq.Config = &tfsdk.Config{
+			Raw:    tftypes.NewValue(tftypes.Object{}, nil),
+			Schema: fwReq.ResourceSchema,
+		}
 	}
 
 	req := list.ListRequest{

internal/fwserver/server_listresource_test.go

@@ -167,6 +167,21 @@ func TestServerListResource(t *testing.T) {
 				},
 			},
 		},
+		"zero-results-on-nil-config": {
+			server: &fwserver.Server{
+				Provider: &testprovider.Provider{},
+			},
+			request: &fwserver.ListRequest{
+				Config: nil, // Simulating a nil config
+				ListResource: &testprovider.ListResource{
+					ListMethod: func(ctx context.Context, req list.ListRequest, resp *list.ListResultsStream) {
+						resp.Results = list.NoListResults // Expecting no results when config is nil
+					},
+				},
+			},
+			expectedStreamEvents: []fwserver.ListResult{},
+			expectedError:        "config cannot be nil",
+		},
 	}
 
 	for name, testCase := range testCases {